BACKGROUND: Clinical antipsychotic trials of intervention effectiveness showed that atypical antipsychotics (AAPs) were associated with significant weight gain and glucose intolerance. A few trials have shown topiramate to reduce weight gain in patients receiving AAPs, although this benefit has not been present in all trials.OBJECTIVE: This study aimed to determine topiramate therapy's impact on weight gain in patients receiving AAPs.DATA SOURCE: A systematic literature search of MEDLINE (1948 to July 8, 2011) and Cochrane CENTRAL (4th Quarter 2011) was conducted.STUDY SELECTION: Eight trials (n = 336 participants) met our inclusion criteria: randomized controlled trial, evaluated topiramate in patients taking AAPs, and reported weight change during the treatment course.DATA EXTRACTION: Two investigators (S.M. and C.I.C.) used a standardized data abstraction tool to independently collect data, with disagreement resolved through discussion. The difference between the mean weight in the topiramate and control groups was calculated as the weighted mean difference with accompanying 95% confidence interval. A random effect model was used for all analyses.DATA SYNTHESIS: Upon meta-analysis, we found that patients receiving topiramate lost weight or had attenuated weight gain compared to control patients (weighted mean difference, -2.83 kg; 95% confidence interval, -4.62 to -1.03).CONCLUSIONS: Our meta-analysis shows that using topiramate can prevent or reduce weight gain associated with AAPs.